Avoid lowering gc-cons-threshold

* lisp/cedet/semantic/wisent/comp.el (wisent--compile-grammar):
* lisp/international/mule-cmds.el (ucs-names):
* lisp/progmodes/ebrowse.el (ebrowse-read):
* test/src/coding-tests.el (benchmark-decoder): Avoid lowering
gc-cons-treshold.

lisp/cedet/semantic/wisent/comp.el

@@ -3427,7 +3427,7 @@ where:
   (if (wisent-automaton-p grammar)
       grammar ;; Grammar already compiled just return it
     (wisent-with-context compile-grammar
-      (let* ((gc-cons-threshold 1000000))
+      (let* ((gc-cons-threshold (max gc-cons-threshold 1000000)))
         (garbage-collect)
 	(setq wisent-new-log-flag t)
 	;; Parse input grammar

lisp/international/mule-cmds.el

@@ -3047,7 +3047,7 @@ on encoding."
 	       (#x1D000 . #x1FFFF)
 	       ;; (#x20000 . #xDFFFF) CJK Ideograph Extension A, B, etc, unused
 	       (#xE0000 . #xE01FF)))
-	    (gc-cons-threshold 10000000)
+            (gc-cons-threshold (max gc-cons-threshold 10000000))
 	    (names (make-hash-table :size 42943 :test #'equal)))
         (dolist (range ranges)
           (let ((c (car range))

lisp/progmodes/ebrowse.el

@@ -794,7 +794,7 @@ and TREE is a list of `ebrowse-ts' structures forming the class tree."
 	     (ebrowse-hs-version header) ebrowse-version-string))
     ;; Read Lisp objects.  Temporarily increase `gc-cons-threshold' to
     ;; prevent a GC that would not free any memory.
-    (let ((gc-cons-threshold 2000000))
+    (let ((gc-cons-threshold (max gc-cons-threshold 2000000)))
       (while (not (progn (skip-chars-forward " \t\n") (eobp)))
 	(let* ((root (read (current-buffer)))
 	       (old-root-ptr (ebrowse-class-in-tree root tree)))

test/src/coding-tests.el

@@ -359,7 +359,7 @@
 	(delete-region (point-min) (point))))))
 
 (defun benchmark-decoder ()
-  (let ((gc-cons-threshold 4000000))
+  (let ((gc-cons-threshold (max gc-cons-threshold 4000000)))
     (insert "Without optimization:\n")
     (dolist (files test-file-list)
       (dolist (file (cdr files))