Only pass isolate parameter to C helper functions that need it.

src/arm/codegen-arm.cc

Index: src/arm/codegen-arm.cc
diff --git a/src/arm/codegen-arm.cc b/src/arm/codegen-arm.cc
index 91c47476caef315ea3ee2b75809ed4fb57d88cab..d5f6aed95ded06defeef04aaf3502d31903c3cf5 100644
--- a/src/arm/codegen-arm.cc
+++ b/src/arm/codegen-arm.cc
@@ -5361,8 +5361,9 @@ void CodeGenerator::GenerateRandomHeapNumber(
   // by computing:
   // ( 1.(20 0s)(32 random bits) x 2^20 ) - (1.0 x 2^20)).
   if (Isolate::Current()->cpu_features()->IsSupported(VFP3)) {
-    __ PrepareCallCFunction(0, r1);
-    __ CallCFunction(ExternalReference::random_uint32_function(isolate()), 0);
+    __ PrepareCallCFunction(1, r0);
+    __ mov(r0, Operand(ExternalReference::isolate_address()));
+    __ CallCFunction(ExternalReference::random_uint32_function(isolate()), 1);
 
     CpuFeatures::Scope scope(VFP3);
     // 0x41300000 is the top half of 1.0 x 2^20 as a double.
@@ -5380,10 +5381,11 @@ void CodeGenerator::GenerateRandomHeapNumber(
     __ vstr(d7, r0, HeapNumber::kValueOffset);
     frame_->EmitPush(r4);
   } else {
+    __ PrepareCallCFunction(2, r0);
     __ mov(r0, Operand(r4));
-    __ PrepareCallCFunction(1, r1);
+    __ mov(r1, Operand(ExternalReference::isolate_address()));
     __ CallCFunction(
-        ExternalReference::fill_heap_number_with_random_function(isolate()), 1);
+        ExternalReference::fill_heap_number_with_random_function(isolate()), 2);
     frame_->EmitPush(r0);
   }
 }