Fix two asan detected memory bugs

I am running through simulate.swift (my port of simulate.cc) with
address sanitizer to discover related bugs.

Besides ones in my port, there are two in MuJoCo:

1. in maketext, the logic to find . is not protected against j is less
   than 0 (due to the decreasing logic above), creating out of bound
   access.

2. in mj_printFormattedData, qfrc_applied should use length nv not nq,
   otherwise out of bound access could be triggered.

Test Plan:

Run through the simulate.cc with asan. Before this fix, when presenting
profiler view, it will trigger bug #1. When print data, it will trigger
bug #2. Both are using model/humanoid/22_humanoids.xml.

src/render/render_gl2.c

@@ -711,7 +711,7 @@ static void maketext(const char* format, char* txt, float num, int txt_sz) {
     }
 
     // '.' found: strip
-    if (txt[j]=='.') {
+    if (j>=0 && txt[j]=='.') {
       txt[i] = 0;
     }
   }