Move jstoi_s to liblegacy.js (#24132)

This function was added alongside `jstoi_q` in #10457, but its
documentation is wrong. `Number("123abc")` does not throw, it returns
NaN.

This function never had any internal usage within emscripten.

Author: sbc100

src/lib/libcore.js

@@ -1642,11 +1642,6 @@ addToLibrary({
   $jstoi_q__docs: '/** @suppress {checkTypes} */',
   $jstoi_q: (str) => parseInt(str),
 
-  // Converts a JS string to an integer base-10, with signaling error
-  // handling (throws a JS exception on error). E.g. jstoi_s("123abc")
-  // throws an exception.
-  $jstoi_s: 'Number',
-
 #if LINK_AS_CXX
   // libunwind
 

src/lib/liblegacy.js

@@ -116,6 +116,12 @@ legacyFuncs = {
   // Legacy names for runtime `out`/`err` symbols.
   $print: 'out',
   $printErr: 'err',
+
+  // Converts a JS string to an integer base-10. Despite _s, which
+  // suggests signaling error handling, this returns NaN on error.
+  // (This was a mistake in the original implementation, and kept
+  // to avoid breakage.)
+  $jstoi_s: 'Number',
 };
 
 if (WARN_DEPRECATED && !INCLUDE_FULL_LIBRARY) {

test/other/codesize/test_codesize_hello_O0.gzsize

@@ -1 +1 @@
-7805
+7806

test/other/codesize/test_codesize_minimal_O0.gzsize

@@ -1 +1 @@
-6123
+6119

test/other/codesize/test_codesize_minimal_O0.jssize

@@ -1 +1 @@
-16149
+16141

test/other/test_unoptimized_code_size_strict.js.size

@@ -1 +1 @@
-49919
+49906