Do not use backtick as opening single quote

Replace it with '. For example, This changes an error message from
failed to load class `java.nio.file.Path'
to
failed to load class 'java.nio.file.Path'

The reason is that the convention of using ` for opening single
quotes looks odd in most modern fonts. For more discussion please
read:

https://www.cl.cam.ac.uk/~mgk25/ucs/quotes.html

Author: Owen

jbmc/regression/jbmc/class-loading-annotations/test-array-value-annotation-on-class.desc

@@ -3,8 +3,8 @@ ArrayValueAnnotationOnClass.class
 --verbosity 10
 ^EXIT=6$
 ^SIGNAL=0$
-Getting class `MyClassA' from file \.[\\/]MyClassA\.class
-Getting class `MyClassB' from file \.[\\/]MyClassB\.class
+Getting class 'MyClassA' from file \.[\\/]MyClassA\.class
+Getting class 'MyClassB' from file \.[\\/]MyClassB\.class
 --
 --
 This test checks that element classes of arrays that are given as values of a class-level annotation

jbmc/regression/jbmc/class-loading-annotations/test-array-value-annotation-on-field.desc

@@ -3,8 +3,8 @@ ArrayValueAnnotationOnField.class
 --verbosity 10
 ^EXIT=6$
 ^SIGNAL=0$
-Getting class `MyClassA' from file \.[\\/]MyClassA\.class
-Getting class `MyClassB' from file \.[\\/]MyClassB\.class
+Getting class 'MyClassA' from file \.[\\/]MyClassA\.class
+Getting class 'MyClassB' from file \.[\\/]MyClassB\.class
 --
 --
 This test checks that element classes of arrays that are given as values of a field-level annotation

jbmc/regression/jbmc/class-loading-annotations/test-array-value-annotation-on-method.desc

@@ -3,8 +3,8 @@ ArrayValueAnnotationOnMethod.class
 --verbosity 10
 ^EXIT=6$
 ^SIGNAL=0$
-Getting class `MyClassA' from file \.[\\/]MyClassA\.class
-Getting class `MyClassB' from file \.[\\/]MyClassB\.class
+Getting class 'MyClassA' from file \.[\\/]MyClassA\.class
+Getting class 'MyClassB' from file \.[\\/]MyClassB\.class
 --
 --
 This test checks that element classes of arrays that are given as values of a method-level

jbmc/regression/jbmc/class-loading-annotations/test-array-value-annotation-on-parameter.desc

@@ -3,8 +3,8 @@ ArrayValueAnnotationOnParameter.class
 --verbosity 10
 ^EXIT=6$
 ^SIGNAL=0$
-Getting class `MyClassA' from file \.[\\/]MyClassA\.class
-Getting class `MyClassB' from file \.[\\/]MyClassB\.class
+Getting class 'MyClassA' from file \.[\\/]MyClassA\.class
+Getting class 'MyClassB' from file \.[\\/]MyClassB\.class
 --
 --
 This test checks that element classes of arrays that are given as values of an annotation at method

jbmc/regression/jbmc/class-loading-annotations/test-class-value-annotation-on-class.desc

@@ -3,7 +3,7 @@ ClassValueAnnotationOnClass.class
 --verbosity 10
 ^EXIT=6$
 ^SIGNAL=0$
-Getting class `MyClassA' from file \.[\\/]MyClassA\.class
+Getting class 'MyClassA' from file \.[\\/]MyClassA\.class
 --
 MyClassB
 --

jbmc/regression/jbmc/class-loading-annotations/test-class-value-annotation-on-field.desc

@@ -3,7 +3,7 @@ ClassValueAnnotationOnField.class
 --verbosity 10
 ^EXIT=6$
 ^SIGNAL=0$
-Getting class `MyClassA' from file \.[\\/]MyClassA\.class
+Getting class 'MyClassA' from file \.[\\/]MyClassA\.class
 --
 MyClassB
 --

jbmc/regression/jbmc/class-loading-annotations/test-class-value-annotation-on-method.desc

@@ -3,7 +3,7 @@ ClassValueAnnotationOnMethod.class
 --verbosity 10
 ^EXIT=6$
 ^SIGNAL=0$
-Getting class `MyClassA' from file \.[\\/]MyClassA\.class
+Getting class 'MyClassA' from file \.[\\/]MyClassA\.class
 --
 MyClassB
 --

jbmc/regression/jbmc/class-loading-annotations/test-class-value-annotation-on-parameter.desc

@@ -3,7 +3,7 @@ ClassValueAnnotationOnParameter.class
 --verbosity 10
 ^EXIT=6$
 ^SIGNAL=0$
-Getting class `MyClassA' from file \.[\\/]MyClassA\.class
+Getting class 'MyClassA' from file \.[\\/]MyClassA\.class
 --
 MyClassB
 --

jbmc/regression/jbmc/classpath-class-incorrect-package/test.desc

@@ -5,7 +5,7 @@ Test.class
 ^SIGNAL=0$
 --
 Java main class: Test
-failed to open input file `Test.class'
+failed to open input file 'Test.class'
 --
 Test.class is not in the right directory corresponding to its package.
 Issue: 2864

jbmc/regression/jbmc/classpath-invalid/test-jar.desc

@@ -4,7 +4,7 @@ Test.class
 ^EXIT=6$
 ^SIGNAL=0$
 ^the program has no entry point$
-^failed to load class `Test'$
+^failed to load class 'Test'$
 --
 --
 symex-driven lazy loading should emit "the program has no entry point" but currently doesn't