Fix extra semicolon outside of a function in NO_SANITIZE

```
internal/sanitizers.h:57:26: error: ISO C does not allow extra ‘;’ outside of a function [-Wpedantic]
   57 |     COMPILER_WARNING_PUSH; \
      |                          ^
```

and so many.

Remove semicolons following pragma, and repeat the given declaration
at the end to consume a semicolon following the macro call.  As many
`NO_SANITIZE` calls including bigdecimal that is a gem have a trailing
semicolon, it was not able to move the semicolon inside `NO_SANITIZE`.

internal/sanitizers.h

@@ -54,10 +54,11 @@
 # include "internal/warnings.h"
 # undef NO_SANITIZE
 # define NO_SANITIZE(x, y) \
-    COMPILER_WARNING_PUSH; \
-    COMPILER_WARNING_IGNORED(-Wattributes); \
+    COMPILER_WARNING_PUSH \
+    COMPILER_WARNING_IGNORED(-Wattributes) \
     __attribute__((__no_sanitize__(x))) y; \
-    COMPILER_WARNING_POP
+    COMPILER_WARNING_POP \
+    y
 #endif
 
 #ifndef NO_SANITIZE

parser_st.c

@@ -154,7 +154,8 @@ nonempty_memcpy(void *dest, const void *src, size_t n)
     _Pragma("GCC diagnostic push") \
     _Pragma("GCC diagnostic ignored \"-Wattributes\"") \
     __attribute__((__no_sanitize__(x))) y; \
-    _Pragma("GCC diagnostic pop")
+    _Pragma("GCC diagnostic pop") \
+    y
 #endif
 
 #ifndef NO_SANITIZE