Don’t call save_re_context

It is an empty function.

mg.c

@@ -1759,7 +1759,6 @@ Perl_magic_methcall(pTHX_ SV *sv, const MAGIC *mg, SV *meth, U32 flags,
     if (flags & G_WRITING_TO_STDERR) {
 	SAVETMPS;
 
-	save_re_context();
 	SAVESPTR(PL_stderrgv);
 	PL_stderrgv = NULL;
     }

regcomp.c

@@ -6054,7 +6054,6 @@ S_compile_runtime_code(pTHX_ RExC_state_t * const pRExC_state,
 
 	ENTER;
 	SAVETMPS;
-	save_re_context();
 	PUSHSTACKi(PERLSI_REQUIRE);
         /* G_RE_REPARSING causes the toker to collapse \\ into \ when
          * parsing qr''; normally only q'' does this. It also alters

sv.c

@@ -14875,7 +14875,6 @@ Perl_sv_recode_to_utf8(pTHX_ SV *sv, SV *encoding)
 	    nsv = sv_newmortal();
 	    SvSetSV_nosteal(nsv, sv);
 	}
-	save_re_context();
 	PUSHMARK(sp);
 	EXTEND(SP, 3);
 	PUSHs(encoding);
@@ -14946,7 +14945,6 @@ Perl_sv_cat_decode(pTHX_ SV *dsv, SV *encoding,
 	dSP;
 	ENTER;
 	SAVETMPS;
-	save_re_context();
 	PUSHMARK(sp);
 	EXTEND(SP, 6);
 	PUSHs(encoding);

utf8.c

@@ -2357,7 +2357,6 @@ Perl__core_swash_init(pTHX_ const char* pkg, const char* name, SV *listsv, I32 m
 	PUSHSTACKi(PERLSI_MAGIC);
 	ENTER;
 	SAVEHINTS();
-	save_re_context();
 	/* We might get here via a subroutine signature which uses a utf8
 	 * parameter name, at which point PL_subname will have been set
 	 * but not yet used. */
@@ -2371,6 +2370,10 @@ Perl__core_swash_init(pTHX_ const char* pkg, const char* name, SV *listsv, I32 m
 	    GvSV(PL_errgv) = NULL;
 	    /* It is assumed that callers of this routine are not passing in
 	     * any user derived data.  */
+	    /* XXX The following comment is out of date.  The
+	           save_re_context() call used to be right after
+		   SAVEHINTS() above, but no longer exists.  Does the
+		   errsv_save bit still apply?  */
 	    /* Need to do this after save_re_context() as it will set
 	     * PL_tainted to 1 while saving $1 etc (see the code after getrx:
 	     * in Perl_magic_get).  Even line to create errsv_save can turn on

util.c

@@ -1533,7 +1533,6 @@ S_invoke_exception_hook(pTHX_ SV *ex, bool warn)
 	SV *exarg;
 
 	ENTER;
-	save_re_context();
 	if (warn) {
 	    SAVESPTR(*hook);
 	    *hook = NULL;