patch 8.2.0751: Vim9: performance can be improved

Problem:    Vim9: performance can be improved.
Solution:   Don't call break.  Inline check for list materialize.  Make an
            inline version of ga_grow().
diff --git a/src/proto/misc2.pro b/src/proto/misc2.pro
index 6c047f3..592c7d1 100644
--- a/src/proto/misc2.pro
+++ b/src/proto/misc2.pro
@@ -59,6 +59,7 @@
 void ga_init(garray_T *gap);
 void ga_init2(garray_T *gap, int itemsize, int growsize);
 int ga_grow(garray_T *gap, int n);
+int ga_grow_inner(garray_T *gap, int n);
 char_u *ga_concat_strings(garray_T *gap, char *sep);
 void ga_add_string(garray_T *gap, char_u *p);
 void ga_concat(garray_T *gap, char_u *s);