make megatest green again

tests/destructor/t6434.nim

@@ -1,6 +1,7 @@
 discard """
   exitcode: 0
   output: ""
+  joinable: false
 """
 
 type

tests/destructor/t7346.nim

@@ -1,3 +1,7 @@
+discard """
+joinable: false
+"""
+
 when not defined(nimNewRuntime):
   {.error: "This bug could only be reproduced with --newruntime".}
 

tests/destructor/tatomicptrs.nim

@@ -11,6 +11,7 @@ deallocating
 allocating
 deallocating
 '''
+joinable: false
 """
 
 type

tests/destructor/tcustomseqs.nim

@@ -16,6 +16,7 @@ discard """
 1 2 6
 1 3 7
 after 6 6'''
+joinable: false
 """
 
 import typetraits

tests/destructor/tcustomstrings.nim

@@ -5,6 +5,7 @@ foo bar to appendmore here
 foo bar to appendmore here
 foo bar to appendmore here
 after 20 20'''
+joinable: false
 """
 
 {.this: self.}

tests/destructor/tdestructor3.nim

@@ -6,6 +6,7 @@ destroy
 123
 destroy Foo: 5
 destroy Foo: 123'''
+joinable: false
 """
 
 # bug #2821

tests/destructor/tdiscard.nim

@@ -1,3 +1,7 @@
+discard """
+joinable: false
+"""
+
 type
   O = object
 

tests/destructor/tmove_objconstr.nim

@@ -7,6 +7,7 @@ test destroyed 0
 3
 4
 Pony is dying!'''
+joinable: false
 """
 
 # bug #4214

tests/destructor/topttree.nim

@@ -8,6 +8,7 @@ discard """
 90.0
 120.0
 8 8'''
+joinable: false
 """
 
 import typetraits

tests/misc/tcast.nim

@@ -2,6 +2,7 @@ discard """
   output: '''
 Hello World
 Hello World'''
+  joinable: false
 """
 type MyProc = proc() {.cdecl.}
 type MyProc2 = proc() {.nimcall.}