enable unsafe for test/ufuzz.js (#2819)

- introduce `unsafe_undefined`
- safer `.toString()` compression

Miscellaneous
- rename `unsafe_Function`

test/compress/functions.js

@@ -218,7 +218,7 @@ issue_203: {
     options = {
         keep_fargs: false,
         side_effects: true,
-        unsafe_Func: true,
+        unsafe_Function: true,
         unused: true,
     }
     input: {

test/compress/issue-1443.js

@@ -4,7 +4,7 @@ unsafe_undefined: {
     options = {
         conditionals: true,
         if_return: true,
-        unsafe: true
+        unsafe_undefined: true,
     }
     mangle = {}
     input: {
@@ -30,7 +30,7 @@ keep_fnames: {
     options = {
         conditionals: true,
         if_return: true,
-        unsafe: true
+        unsafe_undefined: true,
     }
     mangle = {
         keep_fnames: true

test/compress/issue-1588.js

@@ -61,7 +61,7 @@ unsafe_undefined: {
     options = {
         conditionals: true,
         if_return: true,
-        unsafe: true,
+        unsafe_undefined: true,
     }
     mangle = {}
     input: {

test/compress/sequences.js

@@ -288,7 +288,7 @@ unsafe_undefined: {
         if_return: true,
         sequences: true,
         side_effects: true,
-        unsafe: true,
+        unsafe_undefined: true,
     }
     input: {
         function f(undefined) {

test/ufuzz.json

@@ -21,7 +21,13 @@
     {
         "compress": {
             "keep_fargs": false,
-            "passes": 100
+            "passes": 1e6,
+            "sequences": 1e6,
+            "unsafe": true,
+            "unsafe_Function": true,
+            "unsafe_math": true,
+            "unsafe_proto": true,
+            "unsafe_regexp": true
         }
     }
 ]