Bump minimum browser versions

This change bumps out minimum supported browser versions just enough
so we can drop support for output transpilation via babel.

chrome: 74 -> 85
firefox: 68 -> 79
safari: 12.2 -> 14.0

This also means we always support the MUTABLE_GLOBALS and PROMISE_ANY
features, since its no longer possible to target engines without out it.

Author: sbc100

ChangeLog.md

@@ -20,6 +20,12 @@ See docs/process.md for more on how version tagging works.
 
 5.0.6 (in development)
 ----------------------
+- The minimum versions of browser engines supported by emscirpten generated
+  code was bumped, allowing us to remove our internal support for transpilation
+  via babel:
+    MIN_CHROME_VERSION: 74 -> 85
+    MIN_FIREFOX_VERSION: 68 -> 79
+    MIN_SAFARI_VERSION: 12.2 -> 14.0
 - The minimum version of node supported by the generated code was bumped from
   v12.22.0 to v18.3.0. (#26604)
 - The DETERMINISIC settings was marked as deprecated (#26653)